The present invention relates to a fused combination of a plastic lid and a pour spout. While the invention may have wider application, it will be described here in conjunction with a plastic lid and a flexible pour spout fused to the lid which can be collapsed to a position relatively flat with the lid and can be pulled out to an extended position when it is desired to pour liquid from a bucket which is closed on the top by the lid. A preferred embodiment of the invention will be described relative to a combination of a plastic lid intended to close a plastic bucket, and a plastic pour spout fused to the lid and movable between a collapsed position and an extended position.
Such a pour spout cannot be made of a material which has the same thickness as the lid. Such a pour spout must have a relatively thin spout section to permit it to be pressed into a generally flat or collapsed position when not in use, and to be pulled out to an extended position when the spout is to be used for pouring from a bucket on which the lid is attached. In contrast, the plastic lid material must be much more stiff than the pour spout.
It has been known heretofore to manufacture a pour spout attached to a molded lid. Thus, the lid and pour spout are molded separately, and then an attachment operation is carried out to attach the pour spout to the lid. Where a pour spout is to be used, the lid must be molded with a fitting to which the pour spout can be attached. Such a fitting will normally include a solid portion which can be punched out to create a hole where the pour spout attaches. The pour spouts have their own screw cap or the like for closure. If no pour spout is utilized, the lid can function as a normal closure of an open top bucket.
Known pour spouts comprise relatively soft, thin plastic in the spout area combined with a relatively rigid base portion which attaches to the lid fitting. Such base portion may be made of metal, or relatively rigid plastic. Known pour spouts also have screw-on lids or caps, so the spout can be opened and closed. In some cases, the spout will snap onto a fitting portion on the lid, while in other cases the spout may screw on to the lid fitting. In all such cases, the pour spout is attached to the lid after the lid has been molded, and such pour spouts are relatively expensive.
The known pour spouts have significant disadvantages. As noted above, they are relatively expensive, and of course an attachment operation is required after the lid is molded. Beyond that, plastic bucket and lid combinations are often required to be subjected to drop tests to assure that filled bucket can withstand a given drop without the lid disengaging or any of the contents being lost. The various known spouts as described above which snap or screw on to a lid fitting have not performed well when subjected to required drop tests. In addition, there exists a theft problem because the relatively expensive pour spout can easily can be removed from the lid fitting.
The present invention involves a novel method of fusing a pour spout to a lid during the molding of the lid. Thus, the pour spout is molded and is placed in a special steel mold insert which is positioned in the lid mold. When the lid is molded, the previously molded pour spout is molded
One of many advantages of the invention is that the molded pour spout is relatively inexpensive due to its simplicity. The pour spout comprises the usual thin and flexible spout portion, and a relatively thick flange or rim at the bottom. During the molding of the lid, the molten plastic is permitted to surround a relatively thick flange or rim of the pour spout to fuse the base of the pour spout to the lid. At the same time, the mold inserts serve to prevent the molten plastic from engaging the thin spout portion of the pour spout which would be destroyed if contacted by the molten plastic. The pour spout used in the present invention has the usual screw-on cap or the like for opening and closing the spout, and it is collapsible to a flat position as in known in the art.
The pour spout used in the present invention is quite simple and inexpensive compared to the known pour spout which is attached to a lid fitting after the lid has been molded. As described above, the pour spout essentially comprises only the usual flexible spout portion with a cap, and a relatively thick rim or flange at the bottom which is fused to the lid during the molding of the lid. Such a pour spout could not be fused to a lid during the molding of the lid without the special mold inserts which comprise an element of the present invention, because the thin portion of the spout would be destroyed if it were contacted by the molten plastic which forms the lid. Another advantage of the present invention is that fusing of the pour spout and lid during the molding of the lid creates a bond between the pour spout and lid which is especially strong so as to provide significantly improved drop test results. Moreover, the theft problem is eliminated since the pour spout is not removable.
The mold inserts of the present invention comprise a pair of rigid inserts, which may be steel, which fit into the respective halves of a lid mold. In accordance with the preferred embodiment to be described herein, the mold inserts are round, and approximately four inches in diameter. The mold inserts open and close with the two halves of a lid mold, and a molded pour spout is positioned in one of the inserts and held tightly therein when the lid mold and mold inserts are closed. The inserts are designed so that the hot plastic will flow around a relatively rigid base portion of the pour spout to fuse it to the lid being molded, while the inserts prevent the molten plastic from engaging the soft, flexible portion of the previously molded pour spout. The mold inserts are also water cooled to enable them to protect the flexible portion of the pour spout.
There is one prior art technique which bears a superficial resemblance to the present invention. It is known to mold a plastic lid, and to connect a molded pour spout to such a lid by fusing or welding the pour spout to a fitting formed on the lid. Such a method involves attaching the pour spout to a lid after the lid is molded, which is entirely different from the present invention. Beyond that, the final product is very different because the known fusing technique only affects fusing of the spout to the lid at the very bottom surface of the spout. In contrast, the final product of the present invention comprises a spout and lid combination where the spout is fused to the lid around many different surfaces all the way around a rim flange of the spout and not just around a bottom surface. Such extensive fusing of the pour spout to the lid can only be achieved using the present invention where the spout is fused to the lid during the molding of the lid.
One of the important features of the present invention is the use of a rigid inserts to pinch against the thin portion of the previously molded pour spout to create a seal which prevents the flow of molten plastic past the seal. The lid inserts when closed create steel against steel contact, but the mold inserts are designed so that when closed they pinch against the thin section of the molded pour spout without engaging so hard that they destroy the spout.
In the foregoing manner, the pair of mold inserts, which hold the molded pour spout, pinch the thin portion of the pour spout to seal off and protect the thin pour spout section from being contacted by molten plastic while at the same time the molten plastic is permitted to flow around a relatively thick rim or flange portion at the bottom of the pour spout. The relatively thick rim or flange portion of the pour spout, which is thick enough not to be damaged by the molten plastic, is thereby fused to the lid during the molding of the lid. The hot plastic melts the relatively thick rim portion at the bottom of the pour spout to fuse the same with the adjacent portion of the lid as the lid is molded.
During the molding of the lid, the mold inserts are designed to be in close proximity to the thin section of the previously molded pour spout so that, in addition to sealing off the thin section from the molten plastic, the inserts, which are water cooled, serve to cool the thin section of the pour spout to avoid damage which could otherwise be caused by conduction of heat from the relatively thick rim section of the pour spout which is exposed to the molten plastic. It is known in the art to water cool mold inserts, but such inserts have not previously been used for a purpose as in the present invention.
Based on the foregoing description, the pair of mold inserts serve two purposes. First, when the lid mold halves are closed, the closed mold inserts pinch against a thin section of a molded pour spout to seal the same off from contact with the molten plastic, and in addition the water cooled inserts cool the thin section of the spout to protect it against heat conducted from the rim portion of the spout which is exposed to the molten plastic. The mold inserts preferably fit close against the thin section of the pour spout to cool the latter.
The foregoing and other objects and advantage of my invention will be apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings.